22 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull. 



processes. Posterior to the principal lamina there is a smaller 

 accessory one of ovalform with its anterior margin entire. 



The upper and lower lips are regarded as derived from folds 

 of the extreme anterior end of .the esophagus and not as true 

 appendages. Hence they are not referred to definite segments 

 of the head. 



The maxillae differ from the mandibles in their laminar form. 

 The first maxillae are more robust than the second and are pro- 

 vided with spines for tearing the food. The first .pair are made 

 up of an inner and an outer plate and a palp. The palp never has 

 more than two joints, of which the first is shorter than the 

 second. The inner plate may be almost obsolete as in Coro- 

 phiutn and Siphon&cetes, or large and oval and furnished dis- 

 tally and medially with plumose spines, as in the Gammaridae. 

 In the Orchestiidae, the inner plate is long and slender and armed 

 distally with two plumose spines. The inner plate is lacking 

 completely in the Caprellidea and Hyperiidea. The outer plate 

 is always larger than the inner. Its distal margin is armed 

 with a row of short spines of characteristic antler-like or comb- 

 like form which are masticatory in function. The palp articu- 

 lates with the outer plate and its apex usually projects beyond 

 the end of the outer plate. The palp is lacking in Orchestia and is 

 rudimentary in Hyale. In Dexatnine and Phoxocephalus it is 

 of a single joint. The free distal margin is sometimes furnished 

 with setules, but more often it bears stout spines or is serrated. 

 The second maxillae are always small and flexible. They are 

 made up of an outer and an inner plate which bear setae on the 

 inner and distal margins. 



The maxilKpeds belong morphologically to the thorax, but 

 are discussed here, as is usual, in connection with the appendages 

 of the head. The maxillipeds consist of an inner plate, outer 

 plate, and palp. The appendages of the two sides are fused 

 together on the middle line by the proximal joint. The inner 

 plates are formed by an anterior and median expansion of the 

 second joint, and the outer plates by a similar expansion of the 

 third joint; the palp is made up of the remaining joints which 

 may be as many as four. In the Hyperiidea the second seg- 

 ments are fused together completely on the middle line and palps 

 are wanting; in the Caprellidea the fusion of the inner plates is 



