73. NVMERIS ... VERBA COERCES. 'You arrange words in metrical patterns'. Similar wording at Cic Or 64 'mollis est enim oratio philosophorum ... nec uincta numeris ['not in rhythmic prose'], sed soluta liberius'.
Professor E. Fantham points out to me that Ovid may also be playing on numerus 'military contingent' (OLD numerus 9): 'you draft words in squads'.
75-76. NEC AD CITHARAM NEC AD ARCVM SEGNIS APOLLO, / SED VENIT AD SACRAS NERVVS VTERQVE MANVS. Apollo is similarly described at Met X 107-8 (of Cyparissus) 'nunc arbor, puer ante deo dilectus ab illo / qui citharam neruis et neruis temperat arcum'.
76. VENIT = conuenit. In Latin verse a simple verb can carry the sense of any of its compounds, even when this sense is quite different from the usual meaning of the simple verb. Compare Catullus LXIV 21 'tum Thetidi pater ipse iugandum Pelea sensit', "where it is plain that iugandum is for coniugandum, and this leads the reader to the conclusion that sensit is for consensit, where the omission decidedly affects the sense" (Bell 330).
The line should not be taken as an instance of the expression uenire ad manum (OLD uenio 7c), since the idiom's sense 'be convenient' does not fit the context here: for the sense compare Livy XXXVIII 21 6 'quod [sc saxum] cuique temere trepidanti ad manum uenisset' and Quintilian II xi 6 'abrupta quaedam, ut forte ad manum uenere, iaculantur'. Venire in manus offers a somewhat more satisfactory meaning, almost equivalent to 'have, hold' (compare Cic Q Fr II xv [xiv] i 'quicumque calamus in manus meas uenerit' and Persius III 11 'inque manus chartae nodosaque uenit harundo'), but seems to be a separate idiom.
79. QVAE QVONIAM NEC NOS. 'Since she continues to give poetic inspiration to myself as well as to you'. Quae quoniam seems very prosaic, but Ovid uses the phrase again at Tr I ix 53-54 'quae [sc coniectura] quoniam uera est ... gratulor ingenium non latuisse tuum'.
79-80. VNDA ... VNGVLA GORGONEI QUAM CAVA FECIT EQVI. Hippocrene, the spring of the Muses, said to have been created by the hoof-beat of Pegasus. Similarly described at Met V 264 'factas pedis ictibus undas', Fast V 7-8 'fontes Aganippidos Hippocrenes, / grata Medusaei signa ... equi' and Persius prol 1 'fonte ... caballino'.
80. VNGVLA ... CAVA. Professor J. N. Grant points out to me the possible borrowing from Ennius Ann 439 Vahlen3 'it eques et plausu caua concutit ungula terram'.
80. GORGONEI ... EQVI. The same phrase in the same metrical position at Fast III 450 'suspice [sc caelum]: Gorgonei colla uidebis equi'. For the birth of Pegasus from the blood of the Gorgon Medusa, see Met IV 784-86,
81. COMMVNIA SACRA TVERI. Sacra similarly used of poetry at Tr IV i 87, Tr IV x 19 'at mihi iam puero caelestia sacra placebant', EP II x 17 'sunt tamen inter se communia sacra poetis', and EP III iv 67 'sunt mihi uobiscum communia sacra, poetae'. For tueri 'observe, maintain' compare Cic Tusc I 2 'mores et instituta uitae resque domesticas ac familiaris nos profecto et melius tuemur et lautius'.