J0NB 15, 1S83.] 



8CIENCE. 



547 



enumerates over two hundred species, and 

 characterizes as new to science twenty-eight 

 of the genera and more than a hundred of 

 the species. As a continuation of tliis report, 

 preliminary notices of more of the Macrura 

 appeared in the Annales des sciences naturelles 

 for 1881. The explorations of the Travail- 

 leur on the other side of the Atlantic in 1880, 

 1881, 1882, have also brought to light numer- 

 ous new forms, which have been briefly de- 

 scribed or mentioned by Milne-Edwards in 

 several reports upon the work of the Travail- 

 leur. These preliminary reports of Milne- 

 Edwards, though they revealed astonishing 

 discoveries, gave very little idea of the strange 

 new forms discovered ; and the accumulation of 

 such a mass of imperfectly described genera and 

 species was fast becoming a serious obstruction 

 to the work of others in the same department. 

 The work which is the subject of this notice 

 begins to obviate this difficulty by the issuing of 

 advance figures of the new forms referred to. 



This first fasciculus of the work consists of 

 a titlepage and a two-page list of plates 

 p)rintcd bj' some autographic process, and 

 fort3'-four plates, of which thirteen are en- 

 graved, and the rest printed like the titlepage 

 and list of plates. The engraved plates are 

 all proofs before letter, and represent species 

 from the Travailleur expedition only, while 

 the autographic plates represent species from 

 both Travailleur and Blake expeditions, and 

 a few from other sources. None of the plates 

 are numbered in anj^ waj', — an unfortunate 

 omission, which renders references to them dif- 

 ficult ; but the names of the species are printed 

 on them, and on the autographic plates the 

 station and depth are usually added. . The 

 whole number of species figured is sixty-one ; 

 of which thirtj'-one are from the Travailleur, 

 twentj'-six from the Blake, three from the 

 U. S. fish-commission, and one from the 

 Godelfro3' museum. The autographic plates, 

 though rough in appearance, are apparently' 

 quite as accurate as the highly- finished engrav- 

 ings, and have the great advantage of showing 

 the work of the draughtsman only. 



The most remarkable forms figured are from 

 the Blake collection. Phoberus caecus, one 

 of these, a Macruran as large as the lobster, 

 resembles Palaemou in external form, but has 

 rudimentar}' eyes not projecting bej-ond the 

 carapax, and is said to have branchiae like the 

 Astacidae. Xylopagurus rectus is a hermit- 

 crab, which inhabits tubular stems of plants 

 open at both ends, has a bilaterallj- sjunmetrical 

 abdomen with the penultimate somite devel- 

 oped into a calcarous operculum, which closes 



the posterior opening of the tube. Pylocheles 

 Agassizii, another hermit-crab, lives in cavities 

 in hard fragments of agglutinated sand, and 

 has a well-developed, symmetrical abdomen 

 like the tj'pical Macrura. One of the most in- 

 teresting types is Glyphocrangon, represented 

 by three species, the figures of which well 

 illustrate the utilitj' of figures and the slight 

 value of Milne-Edwards's preliminarj^ descrip- 

 tions. The figures show Glyphocrangon to 

 be the same as mj^ Rhachocaris, figured and 

 described in a report on the Blake Crustacea 

 of 1880 {Bull. mus. comp. zool., x.). The 

 genus was described bj' Milne-Edwards as 

 having the telson completel}' consolidated with 

 the preceding somite ; which is not the case, 

 the telson having a movable, though peculiarly 

 constructed articulation, which is like the 

 articulations between the three preceding 

 somites of the abdomen. The structure ot 

 these articulations, which seem to have been 

 wholly overlooked by Milne-Edwards, is so 

 remarkable that I quote the following from my 

 original description ; — 



"In addition to the ordinary hinge at each of the 

 articulations, there is a process arising from the an- 

 terior somite just below the hinge, and curved back- 

 ward and upward concentrically with the hinge ; and 

 this process fits accurately, and is slightly overlapped 

 along its edges by a similarly curved groove in the 

 posterior somite. When the abdomen is completely 

 flexed, the ends of these curved processes project 

 dorsally considerably beyond the grooves ; but, when 

 the abdomen is fully extended, the processes are 

 withdrawn so as to expose the dorsal part of the 

 groove; and in this position, in the contracted alco- 

 holic specimens, the somites are firmly clamped, ap- 

 parently by the pressure of the ends of the processes 

 upon the concave posterior walls of the grooves, and 

 held rigidly extended, so that it is very difficult to flex 

 the somites, unless the tip of the abdomen is pulled 

 bacliward with considerable force, when the processes 

 slide easily through the grooves, and the somites are 

 readily flexed. It is probable that in life, while the 

 extensor muscles of the abdomen are relaxed, the 

 processes move easily through the grooves ; but, when 

 the extensor muscles are strongly contracted, the 

 hinges are clamped, as in the alcoholic specimens, so 

 that the animal can voluntarily hold the telson and 

 the spiny terminal somites of the abdomen rigidly 

 extended as a means of self-defence." 



Another remarkable peculiaritj' of the genus, 

 not noticed by Milne-Edwards, is the articular 

 tion of the coxae of the external maxillipeds 

 with the edges of the carapax. Pontophilus 

 Jacqueti, from the Travailleur expedition, is 

 evidently not a Pontophilus, but a Cei'aphi- 

 lus, and is apparentlj' ideutical with my C. 

 Agassizii from this side of the Atlantic. 



Nearly- half of the species figured apparently 

 belong iu or near Pandalinae and Ephyrinae, 

 which seem to be the most abundant of the 

 deep-water Macrura. S. I. Smith. 



