372 



CEUSTACEA 



FAMILY 9. CHELUEIDAE. 



Body cylindrical; first antennae short, with secondary flagellum; 

 second antennae longer than the first and with blade-like flagellum; 4 

 abdominal segments; 3 pairs of caudal stylets present, the last pair 

 being nearly as long as the rest of the body, but shorter in the female: 

 1 genus. 



CHELTTRA Philippi. With the characters above given: 1 species. 



C. terebrans Phil. Length 6 mm.: New England coast, boring in 

 submerged timbers, and often doing great damage; Europe. 



SUBORDER 3. CAPRELLIDEA. 



But 6 free thoracic segments ; abdomen very rudimentary ; body very 

 elongate : 2 families and about 65 species. 



FAMILY CAPEELLIDAE. 



Body slender and cylindrical; first antennae longer than the second; 

 gills confined to third and fourth free thoracic segments, on which 

 the legs may be wanting: 2 genera, which live among 

 seaweeds and on hydroids, holding on by the 3 pairs of 

 long posterior thoracic legs, with about 50 species. 



1. CAPRELLA Lamarck. Five pairs thoracic legs; 

 mandible without a palp; gills and no legs on the second 

 and third free thoracic segments; abdomen reduced to a 

 small knob bearing a pair of rudimentary legs in the 

 male: many species. 



C. geometrica Say (Fig. 589). Head with an ante- 

 riorly projecting spine; antennae of nearly the same 

 length; length 15 mm.; color variable: Cape Cod to 

 Virginia; very common. 



2. ^GINELLA Broeck. Like Caprella but with a palp 

 on the mandible: several species. 



A. longicornis Krb'yer (Fig. 590). 

 First pair of antennae twice as long 

 as the second; body either smooth or 

 spiny; length 16 mm.; color variable: 

 Labrador to New Jersey; Europe. 



Fig. 589 



Caprella 



geometrica 



(Paulmeier). 



Fig. 590 JZginella longicornis 

 (Paulmeier). 



ORDER 2. ISOPODA.* 



Body usually flattened dorsoventrally and with gills on the abdomi- 

 nal appendages; the anterior pairs of pleopods usually more or less 



* See "Synopsis of North American Isopoda," by Harriet Richardson, Am. Nat., 

 Vol. 34, pp. 207 and 295. "Monograph of the Isopods of North America," by same, 

 Bull. U. S. Natl. Mus., No. 54, 1905. 



