NA TURE 



{Nov. 3, 1887 



system the authors' general conclusions are quite in accord 

 with those of Vosmaer and Polejaeff. In the classifica- 

 tion adopted the order is divided into two sub-orders, 

 Halichondrina and Clavulina. The first of 'these is 

 divided into four families: I. Homorrhaphidae, II. Heteror- 

 rhaphidae, III. Desmacidonidas, and IV. AxinelUdae ; the 

 second into I. Suberitidas, and II. Spirastrellidae. 



Over 200 species or well-marked varieties are described 

 from the Challenger' s dredgings, but all the new species 

 were first diagnosed in the Annals and Magazine of 

 Natural History during the course of last year (1886). 



In reference to the geographical distribution, the authors 

 remark that one cannot fail to notice the small number of 

 stations at which these Sponges were found. Out of a 

 total of 277 distinct stations, only 50 are represented as 

 stations for these Monaxonids, and these are supplemented 

 by 20 localities to which no station-number is attsCcfisd ; 

 and these latter were not, it is to be assumed, deep-sea 

 stations. We cannot agree with the suggestion that these 

 forms were overlooked amongst the " rubbish " in sorting 

 out the contents of the trawls and dredges ; or with the 

 idea that owing to their fragiUty they may have been 

 destroyed. Doubtless the true explanation is that " the 

 Monaxonida are not, on the whole, a predominant group 

 in deep water." 



While not a predominant group in deep water, still no 

 less than 24 species were found at depths between 1000 

 and 2000 fathoms, while 46 occurred between depths of 

 200-1000 fathoms, and 140 species, or exactly double the 

 previous number, were found at depths of from 0-200 

 fathoms. 



The scarcity of Monaxonid Sponges at very great depths 

 is somewhat compensated for by the unusual interest 

 attaching to the ; species which do occur. Among other 

 facts we find that, while the shallow-water forms are 

 characteristically more or less shapeless in their external 

 form or at the very most digitate or ramose, those from 

 below the looo-fathom depth have almost without excep- 

 tion beautifully symmetrical and definite shapes. 



One of the most beautiful and extraordinary of the 

 species described and figured is Esperiopsis challengeri, 

 Ridley : it was taken in some quantity off the east of 

 Celebes Island from a depth of 825 fathoms. From a 

 slightly expanded attached base a slightly curved stem 

 arises, which is composed of densely packed and firmly 

 united stylote spicules : this stem is compressed laterally; 

 numerous short simple branches arise from the concave 

 edge at gradually increasing intervals, the longest of the 

 internodes being at the top ; the main stem and each of 

 these branches terminate in fleshy sponge lamellae, of 

 which there may be six or seven in an apparently full- 

 grown specimen. Each lamella presents the form of a 

 deeply concave, transversely elongated cup : the oscula 

 are confined to the convex surfaces of the lamellae ; the 

 pores are found on the concave surfaces. This species is 

 figured on Plate XVIII. Fifty-one plates accompany this 

 Report. 



The second Report in this volume is a supplement to 

 Dr. L. von Graff's Report on the Myzostomida. It in- 

 cludes the description of seven new forms besides four- 

 teen previously described species, all received from Dr. 

 P. Herbert Carpenter ; tJiese were found by him while 

 investigating the Challenger Crinoids. The author refers 



to the so-called cysts of Atitedon rosacea, but declares 

 that in no one case did he find therein any trace of a 

 Myzostoma or any other encysted organism. On the 

 contrary, both in the various pinnule deformities and in 

 the arm swellings, he found a roundish brown foreign 

 body, which was apparently the cause of the deformity. 

 As to the nature or origin of this body nothing has been 

 determined. Three plates of the new species and one of 

 the cysts of Antedon rosacea accompany this Report. 



The third Report is on Cephalodisctis dodecalophus, 

 Mclnt., by Prof. W. C. Mcintosh. This very remarkable 

 new type of Polyzoon was dredged in the Strait of Magellan, 

 and was, when first found, placed among the Compound 

 Ascidians. The late Mr. Busk, Prof. AUman, and Prof. 

 Mcintosh, referred it to the Polyzoa. At first sight the 

 flexible coenoecium might easily be taken for a sea-weed, 

 but it would seem to spread over the surface of the ground 

 and not to grow erect. Of the numerous branches many 

 anastomose ; the general surface is spiny or fimbriated ; 

 the interior of the stem and branches contains an irregular 

 series of wide canals. The Polypides are described as 

 being perfectly free and at liberty to wander anywhere 

 along the chambers, or even externally through the aper- 

 tures. Each adult Polypide measures, from the extremity 

 of the cephalic plumes to the tips of the pedicel, about 

 2 millimetres. Large buds in various stages of develop- 

 ment arise from the Polypides. The twelve branchial plumes 

 are very conspicuous. The author thinks that Cephalo- 

 discus approaches Rhabdopleura. In an important 

 appendix, by Mr. Sidney F. Harmer, the affinities of 

 this form to Balanoglossus are ably pointed out, and he 

 thinks that this genus (and perhap>s Rhabdopleura also), 

 must be removed from the Polyzoa and placed in 

 Bateson's group of the Hemichordata. Seven plates and 

 numerous woodcuts illustrate this Report. 



Volume XXI. contains but one Report, that on the 

 Hexactinellida, by Prof. F. E. Schulze, of the University 

 of Berlin. This volume is issued in two parts, the first 

 that of the text, comprising over 5oo"pages, and the second 

 consisting of an atlas of 104 plates. 



This is one of the most important of the fifty-three 

 Reports hitherto published. This group of Sponges early 

 attracted the special attention of the late Sir Wyville 

 Thomson ; and it was his intention to describe the 

 HexactineUids of the Challenger Expedition, but the 

 work had s'carcely been seriously commenced at the time 

 of his death. It was fortunate that the services of Prof. 

 Schulze were secured for the writing of this monograph, 

 which is a most acceptable and welcome addition to our 

 literature of this group. 



In this Report, besides the collection made by the 

 Challenger, the results of the previous cruises of the 

 Lightning, Porcupine, Knight Errant, and Triton are 

 also detailed, and the material has been further increased 

 by a collection made at Japan by Dr. Doderlein. 



The HexactineUids are those forms of the Sponges in 

 which the siliceous spicules belong to the triaxial type. 

 Omitting the eighteenth century reference to a Sponge 

 belonging to the genus Dactylocalyx, Dr. Gray was the 

 first in the present century to describe some peculiar 

 " glass rope-like " structures in the British Museum under 

 the name of Hyalonema ; though without recognizing 

 until long afterwards their real affinities. This was in 



