report on the stomatopoda. 13 



The Accessory Copulatory Organs of the Male Stomatopod. 



Before I end the discussion of the phylogenetic relationship between the genera of 

 adult Stomatopoda, I wish to call attention to the importance of figures and descriptions 

 of the complicated structure on the first abdominal appendage of the male. If each 

 description of a new species contained a figure of this structure, the tracing out of the 

 genetic relationship between the species would be greatly simplified ; although a knowledo-e 

 of this organ would, of course, be of no help in our present undertaking, the discovery of 

 the connections between the pelagic larvae and the adults. Unfortunately the Malaco- 

 logists have given little attention to this structure, as it cannot be studied to advantage 

 without removing it from the body and mounting it as a microscopic object. 



In the case of the Challenger specimens Mr. G. B. Haldeman has kindly done this 

 for me, and has also made the drawings of this organ which are here given. 



The endopodite of the first abdominal appendage of the male Stomatopod is furnished, 

 on its inner edge near the tip, with a complicated grasping organ which probably serves 

 for seizing the female, like the grasping forceps of many of the lower Crustacea and some 

 few of the Malacostraca, although I am acquainted with no observations as to their use 

 in the Stomatopoda. The structure has been figured by several observers, but no careful 

 comparative description has ever been published, although it often presents character- 

 istics of specific value, and difiers conspicuously in the different genera. One of the most 

 interesting and valuable peculiarities of the organ is that it seems to illustrate the degree 

 of relationship between the various genera, and an exhaustive study of its modifications 

 in the different species will be a very great aid in tracing the phylogeny and genetic 

 relationship of the various genera and species. Unfortunately, several of the new species 

 in the Challenger collections are represented only by female specimens, and the material 

 is too scanty to afford an opportunity for the exhaustive study of the subject, but I am 

 able to give, with the descriptions of several of the new species, figures and descriptions 

 of this structure, and I hope that these descriptions will serve to incite in some one who 

 has access to larger collections a desire to make a more thorough study of it. 



The endopodite of the first abdominal appendage of the male Stomatopod consists of 

 a large flat basal joint (PI. I. fig. 2, A) separated by a movable transverse suture c 

 from the terminal joint B, which is notched or bilobed at the tip, and thus completely 

 or incompletely divided into an external leaflet a, and an internal one h. The latter 

 carries on the anterior surface of its inner edge, at the line of articulation with the proximal 

 joint, the petasma, or forceps, which consists of three portions : (1) the retinaculum or 

 appendix interna d, which is rounded at its proximal end, prolonged into a long 

 acute or subacute point distally, and with a straight internal edge which is closely 

 set with several crowded rows of hooked spines which interlace on the middle line 

 with those of the corresponding appendage on the opposite side of the body ; (2) the 



