2O CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull. 



called to Calliopius laviusculus, in which the process on the 

 distal end of the last segment of the peduncle of the first 

 antennae may be erroneously regarded as an accessory flagellum. 



In the Caprellidea the number of segments in the flagellum 

 increases regularly with age, and a secondary flagellum is never 

 present. 



The second antennae consist of a peduncle of five joints and 

 a flagellum which is usually multiarticulate. An accessory 

 flagellum is never present. Of the peduncular joints only the 

 last two are well developed, the first two are always very short 

 and the first is fused with the head. In the Orchestiidae the 

 second joint is likewise fused with the head (Fig. i). The 

 second joint is characterized by the fact that the antennal gland, 

 probably excretory in function, opens by means of a hollow 

 conical process on its lower side. This gland cone is conspicuous 

 in Melita and is very minute in Orchestia. In some species the 

 second antennae exhibit marked sexual differences. In Coro- 

 phium the peduncle of the male is much stouter and armed 

 with spinif orm processes ; . in the Lysianassidae the whole 

 antenna is much longer than in the female, and in Ampelisca 

 the male has a row of tufts of specialized sensitive hairs on the 

 dorsal margin of the peduncle of the second antennae as well as 

 on the ventral margin of the first. The flagellum may be reduced 

 to a rudiment made up of only two or three segments, as in 

 Corophium and Siphon&cetes, or may be very long and slender, 

 as in the males of the CEdiceridae and Lysianassidae, and Phoxus. 

 In the Caprellidea of the New England coast, the flagellum is 

 never more than biarticulate. 



Both antennae may be provided with very curious, slipper- or 

 wineglass-shaped appendages known as calceoli, which probably 

 are sensory in nature. These are disposed along one margin of 

 the peduncles or at the distal ends of the flagellar segments. 

 They are seen in Calliopius, Pontogeneia, and the males of the 

 Ampeliscidae. 



Mouth Parts. 



The mouth parts lie partly concealed by the projecting coxal 

 plates of the first gnathopods. As viewed from the side, however, 

 the mandibular palps and the maxillipeds extend forward beyond 

 the general outline of the mass. The mandibular palp is directed 



