72 



PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxxvi. 



In the third pair the proportions are : Meropoclite 2.26 ; carpns 1 ; 

 propodite 1.02; the meroj^odite is no thicker in the male than in the 

 female (proportions 4.3 to 4.5) ; the dactyl is short, with two teeth 

 slightly divergent, the ventral a little stronger and shorter. 



Fig. 42. — Syn.\lpheus brooksi strepsiceros. a, front.\l and .\ntennal region ; c, 



CARPOCERITB ; k', SMALL CHELIPED OF FIRST PAIR; ly FOOT OF SECOND PAIR. 



The height of the telson in the males is a little less than 4 times its 

 posterior margin and 1.23 times its wide base; in the females this 

 last proportion becomes 1.1 ; between the posterior spines, the inner of 

 which are the longer, are found four plumose hairs, with two pairs 

 of simple divergent hairs; the outer uropod bears only two teeth, 



between Avhich is a movable spine. 

 The eggs are very large; I have 

 counted at the most sixteen, and 

 they give rise to very advanced 

 mysis larvae. When freshly laid 

 they measure about 1.1 mm. in the 

 long axis, and they increase to 1.6 

 mm. when the sixth pleosomite at- 

 tains the height of the eyes in the 

 larva folded in the egg ; but females 

 are also frequently found who.se 

 eggs do not exceed 0.5 to O.G mm. in 

 the long axis ; these eggs are, more- 

 over, few (3 to 10) and have a 

 chalky aspect in alcohol; they are 

 probably not destined to develop. These females have in their 

 abdominal pleura the characters of the males, as if they had been 

 castrated by some internal })arasite. 



Named for the late Prof. William K. Brooks, of Johns Hopkins 

 University. 



The species presents some interesting variations. One male from 

 St. Thomas differs from the types in certain points: (1) The spines of 

 the scaphocerite and basicerite are longer; (2) the carpocerite is 



Fig. 43. — Synalpiieus brooksi eleu- 



THER.E. (', CARPOCEUITE ; K, LARGE 

 CHELA, FE.MALE ; k' , SMALL CHELIPED; 

 m, MEROPODITE (IF THIRD PAIR. 



