Cainozoic Lepadidae.—
The genus Lepas (the modern goose barnacles) is represented by isolated plates in the Cainozoic (Janjukian) limestones and marls of Waurn Ponds, and Torquay near Geelong: it also occurs in a stratum of about the same age, the nodule bed, at Muddy Creek, near Hamilton, Victoria (L. pritchardi, Fig. 116). In New Zealand the gigantic cirripede, ?Pollicipes aucklandicus ([Fig. 115 C]), occurs in the Motutapu beds.
Cainozoic Balanidae.—
The Acorn Barnacles are represented in our Cainozoic shell marls and clays by a species of Balanus from the Janjukian of Torquay; whilst two species of the genus occur in the Kalimnan beds at Beaumaris, Port Phillip, in similar beds in the Hamilton District, and at the Gippsland Lakes.
Phyllocarida: Their Structure.—
A large and important group of the higher Crustacea, but confined to the older rocks of Victoria, is the order PHYLLOCARIDA. This seems to form a link between the Entomostraca, including the bivalved Ostracoda and the well-known group of the lobsters, shrimps and crabs. The body of these phyllocarids consists of five segments to the head, eight to the thorax, and from two to eight to the abdomen. The portion usually preserved in this group is the carapace, which covers the head and thorax, and although often in one piece, is sometimes hinged, or otherwise articulated along the back. In front of the carapace there is a moveable plate, the rostrum or beak ([Fig. 117]). There are two pairs of antennae to the head, and the animal is provided with a pair of stalked compound eyes. The thoracic segments are furnished with soft leaf-like legs as in the Phyllopods. The abdomen is formed of ring-like segments, and generally terminates in a sharp tail-piece or telson, often furnished with lateral spines. In many respects the ancient phyllocarids correspond with the living genus Nebalia, which is found inhabiting the shallow waters of the Mediterranean and elsewhere.
Fig. 117—Ceratiocaris papilio, Salter.
Silurian. Lanarkshire.