Chapter V. Porifera. Pp. [138‑151].
Chapter VI. Cœlenterata.
Hydrozoa, pp. [152‑167]. Actinozoa, pp. [167‑173]. Ctenophora, pp. [173‑178]. Summary, etc., pp. [178‑182]. Alternations of generations, pp. [182‑187].
Chapter VII. Platyelminthes.
Turbellaria, pp. [189‑196]. Nemertea, pp. [196‑204]. Trematoda, pp. [205‑210]. Cestoda, pp. [210‑218].
Chapter VIII. Rotifera. Pp. [221‑224].
Chapter IX. Mollusca.
Formation of the layers and larval characters, pp. [225‑273]. Gasteropoda and Pteropoda, pp. [225‑242]. Cephalopoda, pp. [242‑254]. Polyplacophora, pp. [254‑257]. Scaphopoda, pp. [257], 258. Lamellibranchiata, pp. [258‑269]. General review of Molluscan Larvæ, pp. [270‑273]. Development of organs, pp. [273‑288].
Chapter X. Polyzoa.