FEOiVt THE INLAND 8EA OF JAPAN, M9 



margin. The single tooth of the lower margin is situated immediately helovv the fore- 

 most tooth of the upper. The dorsal carina, which is distinctly grooved and which 

 terminates abruptly at the distance of 1 mm. from the posterior margin, widens a little 

 backward ; the also quite distinct, lateral furrows are much broader, nearly twice than 

 the median groove and reach as far backward as the latter. 



The fifth and the sixth segments of the abdomen are carinate, the carina of the sixth 

 terminating in an acute tooth ; on the outer surface of these segments are observed, just 

 below the middle, three short ridges which run parallel with one anothei", the low^er 

 margin of the sixth terminates in a small acute tooth. The telson, little longer than the 

 sixth segment, is deeply grooved in the middle line, and the lateral margins carry on 

 the posterior half three small movable spines ; the middle spine is twice as far from the 

 anterior as from the posterior, and the posterior is as far from the tip as from the 

 anterior spine. 



The external maxillipeds reach to the distal end of the first joint of the antennular 

 peduncle. The legs of the first pair extend to the middle of the antepenultimate joint of 

 the outer footjaws, those of the second pair to the distal end of the penultimate joint, 

 those of the third pair finally reach by their fingers beyond the extremity of the external 

 maxillipeds. The subequal legs of the fourth and fifth pairs reach to the distal end of 

 the antennal peduncles. The basipodites of the legs of the first and second pairs are 

 armed on their inner border with a slender spine, and the arched lower margin of the 

 following joint terminates, in the first pair of legs, in a very small acute tooth (no spine). 



The thelycum (PI. 33. fig. 69) is composed of two lateral walls, the outer surface of 

 which is flattened, triangular, and narrowing somewhat anteriorly ; the inner margins 

 of these plates are in contact along their posterior half, whereas tbey diverge along 

 the anterior. The two lateral walls lean anteriorly on an arched transverse piece, 

 situated between the coxai of the lourth pair of legs posteriorly and bounding the 

 cavity anteriorly ; this transverse piece carries anteriorly a concave protuberance, barely 

 as long as the transverse piece itself, and terminating anteriorly in a small subacute 

 tooth. 



The thelycum of the typical Japanese Pen. latisulcatus differs apparently by the 

 lateral plates, which are in contact with each other nearly along their whole length, 

 and the protuberance has also a different form. Perhaps this species may therefore 

 eventually prove to be distinct, though I fully agree with the opinion of Lanchester 

 (in Proc. Zool. Soc. 1901, vol. ii. p. 571), " that too little is known about the thelycum, 

 and its possibly seasonal varieties within the same species, to justify the founding of 

 a new variety on this character." 



Probably one female from Thursday Island should be referred to Fen. caniculatus, 

 Oliv., var. anstraliensii,; Sp. Bate, but I hesitate to do so, as this variety is still 

 insulficiently known. 



