No. 26.] ARTHROSTRACA OF CONNECTICUT. 133 



First gnathopods larger than second and showing consider- 

 able differences usually in the two sexes. First and second pereio- 

 pods glandular. Last pair of pereiopods the longest. 



Terminal uropods biramous, not elongate. Telson simple. 



Microdeutopus Costa. 



Body slender, slightly compressed ; coxal plates comparatively 

 small. 



Mandibles strong, with palp of moderate size and having 

 terminal joint slender. First maxillae with inner plates small and 

 furnished with a single apical seta. Maxillipeds with palp not 

 very large. 



First antennae longer than second and provided with a distinct 

 accessory flagellum. 



Gnathopods in female comparatively small, the first pair 

 being a little larger than the second pair; propodus imperfectly 

 subchelate; that of second pair narrow and with palm nearly 

 transverse and very short. First gnathopods in male greatly 

 developed and with carpus extremely large and swollen, forming 

 with the propodus and dactyl a kind of chela. First and second 

 pereiopods glandular. Three posterior pereiopods rapidly in- 

 creasing in length and with basal joint but little expanded. 



Terminal uropods not extending beyond the others; rami 

 sublinear and sparsely spinous. Telson large and thick, oval 

 with a dorsal fascicle of spines on either side of the obtusely 

 rounded tip. 



Microdeutopus gryllotalpa Costa. 



1853. Microdeutopus gryllotalpa, Costa, Rendiconto d. Soc. 

 Reale Borbonica, Ac. d. Sci., n. sen, vol. 2, p. 178. 



1873. Microdeutopus minax, Smith, Rep. U. S. Com. Fish., 

 vol. i, p. 562. 



1896. Microdeutopus gryllotalpa, G .O. Sars., Crust. Norway, 

 vol. i, p. 543, pi. 192, fig. 2. 



Eyes small, round, deeply pigmented. 



First antennae more than half as long as body ; second joint of 

 peduncle a little longer than first and as long as head, third joint 

 short ; principal flagellum slender, of about twenty segments and 

 longer than peduncle; accessory flagellum one- jointed and not as 

 long as first joint of principal flagellum. 



