398 DE. J. G. DE MAN ON CEUSTACEA CHIEFLY 



discernible. Tlie median acute spine on the intestinal region is twice as long as the 

 lateral ones. The carapace is marbled with red on either side of the median ridge, on 

 each side of the front, and on the hepatic regions. 



ARCANIA, Leach. 



Arcania heptacantha (de Haan). (PL 31. figs. 8-10.) 



Iphis heptacantha, de Haan, in Herklots, ' Symbolse carciaologicae : Etudes sur la Classe des Crustacds/ 

 Leyde, 1861, p. 27. 



Two males and two sterile females of somewhat larger size, from the Inland Sea of 

 Japan, deep water. 



Through the kindness of the Direction of the Leyden Museum I was enabled to 

 compai'e these specimens with the single type of Iphis heptacantha, de Haan, a descrip- 

 tion of which seems not to have appeared. This type specimen, tlie locality of which is 

 unknown, is an adult female of larger size than the Japanese specimens ; legs and foot- 

 jaws are unfortunately wanting. The Japanese specimens no doubt belong to this 

 species. 



The cephalothorax of de Haan's type specimen is a little broader in proportion to its 

 length ; but this may be explained by its larger size (compare the measurements). 

 Alcock's description of Arc. septemspinosa (Fabr.), Leach (in Journ. Asiat. Soc. Bengal, 

 vol. Ixv. pt. II. no. 2, 1896, p. 265), is applicable to de Haan's type oE Arc. heptacantha 

 except as regards the length of the spines and perhaps also the following. The cardiac 

 and intestinal regions are also separated on each side by a moderately deep groove 

 from the branchial regions, which, according to Alcock's description, does not seem to 

 be the case in Arc. septemspinosa. In Arc. heptacantha the surface of the carapace is 

 finely granular ; on the gastric, cardiac, and intestinal regions the granules are a little 

 larger than on the branchial ; from each of the two spines with which the latter are 

 armed a somewhat irregular row of granules runs forward and inward on their surface ; 

 these granules have the same size as those of the gastric region, but between these rows 

 the granulation is finer than on the median regions. The concavity just behind the 

 crease or pucker that separates the hepatic from the branchial regions and the upper 

 surface of the front are smooth. The lateral spines, that are somewhat directed backward 

 and slightly curved upw^ard, measure in de Haan's type specimen 6 mm., i. e. almost 

 one-third the breadth of the carapace without the spines ; the median spine on the 

 transversely and longitudinally convex intestinal region, which is a little directed upward, 

 is the shortest of the seven spines, measuring 1'75 mm., not quite one-third the length of 

 the lateral sjoines. The four otlier spines, which have nearly the same size, are 2'4 mm. 

 long, so that they appear a little larger than the spine on the intestinal region, measuring 

 a little more than one-third the lateral spines. Exclusive of the spines, the cei^halo- 

 thorax, which is strongly convex transversely and as much longitudinally, appears in the 

 Leyden type a little broader than long, in the largest of the Japanese specimens (a sterile 

 female) nearly as long as broad. In the latter specimen the lateral spines are 3'25 mm. 

 long, about one-fifth the width of the carapace without the spines, so that they are 



