CALIFORNIA STALK-EYED CRUSTACEA. 235 



Spirontocaris spinus (Soiverby). 



Cancer spi7ius Sowerby, Brit. Misc., 1806, p. 47, PI. XXI. \ . uajLlju ^ 



Hippolyte «jfw*«t?;^Ow«N, Appendix to Boss's Second Voyage, 1835, p. V f 



Ixxxiii, PI. ili, fig. -2. ■ 

 Spirontocaris spinus Bate, Challenger Reports, Vol. XXIV, 1888, p. 596, 



Pis. CVI and CVII. 

 For further references and synonyms, see Bate, 1. c. 



A short, robust species.. Rostrum beginning at the posterior end of the 

 carapace as a carina, which is strongly arched and armed with four or five 

 large teeth; the lamina or rostrum proper is high, much shorter than the 

 carapace, more or less truncated at the tip, and armed above with several 

 teeth which decrease in size anteriorly; lower side strongly curved distally 

 and armed with one or more teeth. Two supra-orbital teeth on either side, 

 the posterior one the larger. A prominent antennal spine and a smaller - 

 spine at the autero-inferior angle of the carapace. Outer spine at the base 

 of the antennules large, about reaching the tip of the third joint of the 

 peduncle. Acicle extending beyond the rostrum. Maxillipeds stout, ex- 

 ceeding the rostrum, the terminal joint flattened, about four times the 

 length of the preceding joint, the tip armed with spines; exognath not 

 reaching the tip of the antepenultimate joint. First pair of chelipeds 

 rather slender. Third carpal joint of the second pair longer than the first 

 and second combined, but not twice as long. Dactyls of the ambulatory 

 legs short and spiny below. Third segment of the abdomen produced 

 backward into a prominent beak. 



This species has been reported from very near our 

 limits, and as it is very closely allied to S. lanieUicornis 

 (Dana), and will probably be found to occur along with 

 that species, this description is inserted in order to dis- 

 tinguish the two forms. I have not seen any represen- 

 tatives of S. spinus from the Pacific coast, but Dana's 

 description and figures of lamellicornis agree quite closely 

 with specimens of spinus that I have from the north 

 Atlantic. It is possible that the so-called western rep- 

 resentatives of spinus belong to Dana's species, for the 

 differences between the two forms are not greater than 

 those often found between widely separated members of 

 an extensively distributed species. The third joint of 

 the carpus of the second pair of chelipeds is somewhat 



