I. '08. 140 



1 have followed Smith and Faxon in placing Milne-Edwards' 

 Jdcquidi {^ Agassizi) under Sclerocrangon and this I do not 

 doubt to be correct even though it becomes rather difficult to 

 frame a definition which will exclude the genus Crangon. 

 Now that the arthrobranch on the third maxillipede is known 

 to be absent in Crangon antarcticus and possibly also in other 

 species of that genus., the sculpture of the caraj^ace (a most 

 unsatisfactory character in Crangonidae) is almost the only 

 feature available. The reduction of Sclerocrangon to the rank 

 of a sub-genus, as suggested by Ortmann, will perhaps solve 

 the difficulty, but further investigation may show that the 

 sternal spines of the male and the greatly abbreviated meta- 

 morphosis (v. Sars, 1890, and Wollebaek, 1907) afford satis- 

 factory indications of its generic validity. 



Two groups of species are comprised in this genus ; one con- 

 tains such forms as horeas, salehrosus, atrox, and ferox, while 

 the other includes Jacqueti, niunita, procax and other allied 

 species.^ This second group, although properly regarded as 

 belonging to Sclerocrangon, is nevertheless much more closely 

 allied to Crangon than the first. 



Sclerocrangon Jacqueti (A. Milne-Edwards). 



PL XXII, figs. 7-10. 



Poniophilvs Jacqueti, A. Milne-Edwards, 1881. 

 Pontophilus Jacqueti, A. Milne-Edwards, 1882. 

 Ceraphilus Agassizi, Smith, 1882, PI. vii, figs. 4-5a. 

 Pontophilus Jacqueti, A. Milne-Edwards, 1883, PL 40. 

 Ceraphilus Agassizi, Smith, 1885. 

 Sclerocrangon Agassizi, Smith, 1887. 



The rostrum consists of an acutely pointed spine, which 

 trends upwards and is concealed when viewed from above by 

 the long anterior median spine of the carapace ; it is rather 

 short and does not reach the tips of the eyes. The carapace 

 is rather broad ; both it and the abdomen are covered with a 

 short and very sparse pubescence. The outer orbital angle is 

 defined by a sharp spine about as long as the rostrum , but con- 

 siderably shorter than that which terminates the broadly ex- 

 panded lateral angles. A median dorsal carina extends the 

 whole length of the carapace ; the prominent anterior spine 

 overhangs the rostrum, reaching beyond its apex and a second 

 stout forwardly directed spine is situated on the cardiac 

 region ; between these two a small tubercle is usually present. 

 On each side of the median carina is found a gastric spine, and 

 below this a strong hepatic spine supported by two carinae, 

 one of which runs backwards to the posterior edge of the cara- 

 pace, while the other is less pronounced, leading downwards 



1 Miss Rathbim (1904) has described several very closely allied species 

 belonging to this group under the genus Crangon. 



