1878.] MR. E. J. M1ERS ON THE PEN^ID.E. 303 



in the female of Penceus, but is not divided by a median fissure) is 

 of the same corneous consistency. All the legs, except the fifth 

 rudimentary pair, are furnished with an exopodite. There is a spine 

 on the under surface of the second joint of the legs of the first three 

 pairs, that on the third pair of legs very small. 



Hab. Mangalur (Mangalore), west coast of India. 



Collected by Dr. G. E. Dobson, to whom I have much pleasure 

 in dedicating the species. 



I have examined four specimens of this species, all of which are 

 certainly females. One of these has been presented by Dr. Dobson 

 to the trustees of the British Museum. The fact that no males 

 have yet been observed renders it possible that the rudimentary and 

 indurated condition of the fifth pair of legs may be peculiar to the 

 female sex — an opinion shared both by Dr. Semper and Mr. Wood- 

 Mason, who have seen the specimens ; and as the mouth-appendages, 

 although presenting some peculiarities, do not depart widely in struc- 

 ture from the type usual in Penceus, I think it advisable until more 

 specimens shall have been examined, to retain the species in that 

 genus. Should further researches, however, prove that the rudi- 

 mentary condition of the fifth legs exists in both sexes, the name 

 Manyahira may be adopted to designate the genus, which will be 

 characterized not only by the above-mentioned character, but also 

 by the triangular shape of the terminal joint of the mandibular pal- 

 pus (which is less delicate and transparent in texture than is usual 

 in Penceus), and the slender outer maxillipedes. The species will then 

 stand as Mangalura dobsoni 1 . 



The form of the fifth pair of legs is not analogous with that cha- 

 racteristic of the very different genus Sergestes, wherein these 

 members, although rudimentary, are very slender, and similar in 

 structure to the preceding pairs. 



In the form of the rostrum P. dobsoni resembles the Penmus 

 sculptilis of Heller, from Java (Voy. Novara, Crust, p. 122, pi. xi. 

 fig. 1) ; but, besides the characters derived from the fourth and fifth 

 pairs of legs, which are of the normal form in P. sculptilis, that 

 species differs, if the figure be correct, in the much longer flagella of 

 the antenuules, and in the absence of a notch in the posterior mar- 

 gin on the sides of the first and second postabdominal segments, in 

 the form of the first postabdominal segment, which is rounded at its 



1 Since writing the above, Professor Wood-Mason has discovered, among speci- 

 mens of P. dobsoni from the same locality (Mangalore), a single male individual, 

 in which he observed that the fifth legs are fully developed, and which, by his 

 kindness, I am now enabled to figure (see PI. XVII. fig. 2, /). It is of very small 

 size, not much more than half as large as the females described by me, which 

 it in all respects resembles, except in the fifth legs. These are very slender and 

 elongated, longer, in fact, than those of the preceding pair, with the dactylus 

 much shorter than the preceding joint. The fact, therefore, that the rudimen- 

 tary condition of the fifth legs is a sexual character peculiar to the female may 

 be regarded as definitely established ; nor does it seem that this can possibly 

 be accidental, or due to the loss of the legs and subs?quent induration of the 

 joint, as the indurated terminal lobe is of the same shape on both legs in all 

 four of the specimens seen by me, and I have never observed a similar condition 

 of the joint in any other specimen of the genus. 



