NO. 2286. THE NEW COPEPOD FAMILY SPHYRIIDAE— WILSON. 581 



This gives a total of 15,000 to 20,000 for each string. Such an excep- 

 tional number is explained when we recall that the host of this para- 

 site is a deep-sea fish, living at a considerable depth, wdiich adds 

 greatly to the difficulty experienced by the larva of the copepod in 

 finding a host. 



The abdomen is on a level with the dorsal surface of the genital 

 segment ; it has the form of a spherical laiob, split lengthwise at the 

 tip by the anus. It is completely fused with the genital segment, 

 and from the fused dorsal surface arise the posterior processes. 

 These are covered, not with true cylinders, as in R. comuta and 

 B. edwardsii, but with elongated cones which taper from the point 

 of attachment to the distal end. This end is sometimes enlarged 

 and more or less spherical and sometimes divided into two short 

 branches. Each process carries about 40 or 50 of these cones. 



The first antennae are reduced to tiny knobs on the dorsal surface 

 of the head; the second antennae are probably replaced by the 

 spherical processes at the anterior margin of the head, although in 

 the adult they have lost all traces of appendages. The mouth tube 

 is on the front of the head and ventral to these processes; it does 

 not project from the surface, but is supported by a chitin frame- 

 work provided with muscles which probably make it more or less 

 protrusible. On either side of the mouth is a small rounded papilla, 

 tipped with a spine, which represents the first maxilla. Ventral to 

 the mouth is a similar pair of small knobs, each tipped with two 

 spines, which are the second maxillae. Farther back on the ventral 

 surface at the base of the fused ventral processes and in front of 

 the groove differentiating the head is a pair of rudiments which 

 probably represent the maxillipeds. They correspond in position 

 with those of Sphyrion, but for certainty younger stages of the 

 female must be examined. 



On examining the internal morphology of the trunk we find the 

 anterior portion of the enlarged intestine covered with processes. 

 These are apparently arranged in longitudinal rows like those in 

 Shyrion, but the anterior ones are many times the length of the 

 posterior ones and are profusely branched, so that they fill the 

 entire cavity of the trunk for the anterior fourth of its length, and 

 their tips are flattened against the inside of the walls of the trunk. 

 They then diminish rapidly and regularly in length and in com- 

 plexity of branching and cease at about the center of the trunk. 

 They thus form a conical mass filling the entire anterior diameter 

 of the trunk and then tapering down to the diameter of the intestine. 

 No dorso ventral muscles can be seen in this portion of the trunk, 

 but there is a bundle of them just behind these processes near the 

 lateral margin and another farther back and nearer the intestine. 

 The cement glands are at the posterolateral margins of the genital 



