283 DISCOVERY REPORTS 



in. Tergum of seventh thoracic somite absent except for small lateral portions which are con- 

 tinuous with the coxal plates, these are of normal size; hindmost suture of sixth thoracic 

 somite complete; third to fifth thoracic somites separated from their coxal plates by sutures. 



A. Head triangular in shape, with apex directed backwards and produced into a large median 

 spine ... ... ... ... ... ... ... ... ... 36. S. pallida, Beddard. 



B. Head four-sided ; pointed tubercles along the posterior margins of the anterior thoracic 

 somites, and median dorsal tubercles on all the segments ... ... t,-]. S. tuherculaia, Gmht. 



DESCRIPTION OF SPECIES 



I . Serolis beddardi, Caiman (Fig. 3). 



S. beddardi. Caiman, 1920, p. 299, figs. 1-3. 

 Occurrence. St. 174: South Shetlands, 5-10 m.; 4 J(J, i ? (b.) and 9 immature specimens. 



Diagnostic characters. The largest male in the collection measures 22 mm. in 

 length and 17 mm. in greatest breadth, a size approximately the same as that of 

 Caiman's specimen; the adult female is incomplete, but has a breadth of 15-5 mm., 

 which is I mm. less than that of Caiman's largest specimen. 



Fig. 3. Serolis beddardi, Caiman. 

 a, cutting edges of mandible: x 20. b, second thoracic appendage: x 7. 

 c, third thoracic appendage of ,^: x 16. d, type of setae found on limbs. 



The dorsal surface of the head and body segments is strongly sculptured and the 

 terminal segment is studded with rounded tubercles which lie between the median and 



