60 



THE ROYAL SOCIETY OF CANADA 



istics that there can be no doubt that the simple cypris-larva obtained 

 in a collection from Passamaquoddy Bay is to be assigned to the same 

 genus. 



The shell, which is rather flat, has an oval outline, being a little 

 broader posteriorly, and measures about 0-82 mm. in its long diameter 

 with a greatest breadth of 0-46 mm. The body is not however, al- 

 together enclosed by the shell, almost the entire abdomen projecting 

 beyond it posteriorly, while ventrally the thoracic appendages project 

 extensively and the maxillse slightly (Fig. 12). There are no indica- 

 tions of either the naupliar or compound eyes. 



The antennse (Fig. 13) are short 4-jointed appendages. The 

 terminal joint terminates in a strong recurved hook, near the base of 



which are three short setae, while some 

 distance from it is a longer seta borne 

 upon a well-marked tubercle. To the 

 basal part of the joint a long sensory 

 filament (the base of which is all that 

 is shown in fig. 13) is attached and 

 thence extends backwards almost to 

 the posterior extremity of the shell. 

 The second joint bears two spines, 

 closely approximated, on its dorsal 

 surface, but the other two joints are 

 unarmed. It was not possible to make out all the details of the 

 mouth parts; the maxilla; (Fig. 14) appear to be fused with the lip 

 structures and terminate in three processes, one of which is in the 

 line of the axis of the limb, while the other 

 two are recurved and hook-like. 



The thorax consists of five segments 

 each of which bears an appendage. These 

 appendages, (Fig. 15) are all biramous and 

 consist of two basal joints, the proximal 

 of which is elongated and ciliated upon its ^'^- ^^- Dendrogaster larva. 



X,, . . ^. MaxjUa. 



outer border. 1 he rami consist ot two 



joints in each case, although 

 the proximal one of the 

 outer ramus appears to be 

 fused with the distal basal 

 joint. Long^etae are borne 

 upon'the terminal joints of 

 each ramus, three upon that 

 Fig. 15. Dendrogaster larva. of the inner ramus, and four 



Thoracic appendage. on that of the outer one. 



Fig. 13. Dendrogaster larva. 

 Antenna, s, basal portion of 

 sensory filament broken off. 



