38 U.S. NATIONAL MUSEUM BULLETIN 278 



these, C. acutifrons f. angusta (1903), borealis (1903), incisa (1903), 

 and verrucosa (1903) (= C.verrucosa Boeck, 1871b) have since been 

 given specific rank. In the present paper one other variety, C. acuti- 

 frons f. andreae, is accorded specific rank, leaving 14 varieties in 

 question. 



The varieties C. acutifrons f. typica (1890), minor (1890), tabida 

 (1890), and tibada (1903) differ from the remaining varieties pri- 

 marily by the distal position of the poison tooth on the palm of 

 the propodus of gnathopod 2. Mayer recognized C. acutifrons f. 

 typica and minor from Bio de Janeiro, Brazil, the latter variety 

 being based on a smaller individual than the former. Kr0yer (1842- 

 43) described C. dilatata from Rio de Janeiro. All of the above- 

 mentioned varieties should be assigned to C. dilatata. Juveniles of 

 this species bear a small proximal tooth on the pahn of gnathopod 

 2, which is very short and spinelike and is not present on individuals 

 larger than approximately 8 mm. 



In 1903 Mayer changed the 1890 variety tabida to tibada and 

 recognized C. tabida Lucas, 1849, as a different variety. C. acutifrons 

 f. tabida (1903) (==C. tabida Lucas, 1849), C. acutifrons f. simulatrix 

 (1903), C. pilimana Dougherty and Steinberg, 1953, and C. obtusi- 

 frons Utinomi, 1943c, differ from the remaining varieties by the lack 

 of a poison tooth on the palm of gnathopod 2. Specimens of the 

 first two varieties and of C. obtusifrons have not been examined so 

 I cannot make any statement on their validity. 



Caprella acutifrons f. cristibrachium (1903) lacks a triangular pro- 

 jection on the cephalon and the shape of gnathopod 2 is quite 

 different from that of the other members of the C. acutifrons group. 

 It is doubtful that it is a variety of this group and probably should 

 be given specific rank. 



The remaining varieties, C. acutifrons f. carolinensis (1890), Virginia 

 (1890), testudo (1903), gibbosa (1890), lusitanica (1890), natalensis 

 (1903), porcellio (1903), and neglecta (1890), are quite similar in the 

 shape of gnathopod 2 and general body form. In the first five varieties 

 the palm of the propodus of gnathopod 2 is quite setose and in the 

 last three varieties and C. angusta the palm is scarcely setose. I have 

 been unable to find other distinguishing characters for these varieties, 

 so I have tentatively assigned them to the species C. penantis. 



Dougherty and Steinberg (1953) gave C. acutifrons f. angusta, 

 incisa, and verrucosa specific rank. These varieties occur together 

 on the California coast and have been collected simulatneously from 

 the same hydroid. Since they are sympatric and no morphological 

 intergradations were observed, all of these varieties cannot be ascribed 

 to the same species. I agree with Dougherty and Steinberg's decision 

 to give them specific rank; however, they do not state how C. 



