128 PROCEEDINGS OF THE IfTATIONAL MUSEUM vol.84 



up and forward and is divided at the end into two apposed, pointed 

 prongs, the lower of which is shorter and slendered (fig. 16, «;, h). 



Males with a comb of fine hairs beneath the last joint of the first 

 three pairs of legs; the under side of the last joint of the ensuing 

 legs, sometimes as far back as the sixteenth pair, with a low, velu- 

 tinous pad on the distal half except on the last few pairs of these 

 legs where the pads decrease in size and vanish. Females with a 

 comb of hairs beneath the outer joint of the first two pairs of legs 

 as in the other species. 



Type.—Msi\e, U.S.N.M. no. 1246. 



Remarks. — Numerous specimens collected 15 miles north of 

 Ensenada, Lower California, on the Tiajuana Road, May 3, 1923, by 

 H. G. McKeever. Additional specimens were found in the same 

 locality on January 7, 1925, by H. G. McKeever and Dr. O. F. Cook. 



COLACTIS TIBURONA (Chamberlin) 



Lysiopetalum ti'buronum Chamberlin, Proc. Califomia Acad. Sci., ser. 4, vol. 12, 

 p. 402, 1923. 



It is evident that this species! belongs in Colactis or Heptium^ as 

 the first segment was described as having only 10 crests; secondary 

 crests of the poriferous segments not reaching the posterior margin 

 of the segments; and the gonopods, as illustrated, might allow it to 

 be assigned to either genus. As the seventh legs of the male were 

 not de-scribed as being reduced in size the species is referred to 

 Coldctis, which has the seventh legs of normal size. The point of 

 transition to the full number of doi-sal crests was not stated. 



COLACTIS QUADRATA, new species 



Figure 16, e, f ; Plate 3, Figure 5 



Diagnosis. — Closer relationship with O. tihurona (Chamberlin) 

 than with any other species is indicated by the shape of the eye 

 cluster, the size and proportions of the body, and the form of the 

 gonopods, although these lack the slender, erect, serrate structures 

 figured by Chamberlin for tihurona. 



DescHption. — Body stout, noticeably dejiressed in both sexes, 17 

 to 34 mm long and 1.6 to 2.7 mm broad, composed of 49 to 61 seg- 

 ments (pi. 3, fig. 5). 



Eye cluster distinctly quadrangular, composed of about 51 ocelli 

 in 7 or 8 rows, counting downward from the top of the head, the 

 ocelli distributed as follows : 5, 7, 8, 8, 8, 8, 7, or 3, 5, 7, 7, 7, 8, 7, 7 ; 

 sense organ in front of rows 2 and 3, or 3 and 4, of the cluster. 



First segment with the inner crests crossing the posterior two- 

 fifths, the four inner crests decidedly closer together than the other 



