REPORT ON THE CALCAREA. 7 



Sycandra arctica, Sycandra ramosa, Sycandra comprexm, Sycandra utriculus, 

 and Sycandra hystrix. For my own part I must emphatically deny their " intercanal- 



less " nature. It will be proved later that the seventeen species just named belong 

 not to seven, but only to three genera, Sycon, - Grantia, and Amphoriscus. I found 

 amongst the Challenger sponges the representatives of all the three genera, I bud 

 examined also Sycon utriculus (Sycandra utriculus, H.), Grantia compressa (Sycandra 

 compressa, H.), and Amphoriscus chrysalis (Sycilla chrysalis, H.), and wish to lay stress 

 upon the fact that the specimens of Sycon utriculus and Auqihoriscus chrysalis were 

 obtained from the collections revised twelve years ago by Prof. HEeckel himself, and 

 that Grantia compressa is a sponge so well known that there can be no doubt that 

 the specimens I have had for investigation belonged to this species. Though not 

 nearly so regular as in some other cases, the intercanals could always be very easily 

 found — their course in Sycon arcticum and Grantia tuberosa is represented in PI. III. 

 figs. 5 and 6, in Amphoriscus poculum and Amphoriscus elongatus in PL IV. figs. 4 

 and 5. And there is no doubt that what Hasckel declares to be " dermal ostia " 

 and " dermal pores " in the individuals of his " Syconusa-type " were merely the pores of 

 the intercanals, and that what he calls "conjunctive pores" (loc. cit., p. 260), these 

 latter uniting, according to him, the cavities of the radial tubes, were nothing but 

 the common pores on the side-walls of the radial tubes connecting these latter with the 

 intercanals. To any one who will notice Prof. Hseckel's remark (loc. cit., Bel. i. p. 248) 

 that these ""conjunctive pores " are best to be observed in sections of dry Sycones, the error 

 into which he fell will be easily comprehended. The refutation of these erroneous 

 statements has not only an anatomical, but also a systematic weight. There is in the 

 genus Sycandra a whole sub-genus, whose principal character is, according to Hseckel, the 

 non-existence of the intercanals, and I fancy I am very near to the truth in my supposition 

 that it was merely the finding of quite evident intercanals which induced Dr. Vosmaer, in 

 his report on the sponges collected by the " Willem Barents." 1 to put a query before his 

 diagnosis of the three Calcarea determined by him as Sycandra compressa, Sycandra 

 utriculus, and Sycandra arctica (loc. cit., p. 4). These three Sycones possess such a charac- 

 teristic set of spicules that I really cannot find any other explanation, except the above 

 mentioned, for Dr. Vosmaer's remark that the specimens in question being very small he 

 could not obtain sections enough for a thorough examination. 



With regard to the Leucones, there are in Prof. Hseckel's Monograph still more 

 serious errors. He distinguishes four modifications of their canal system. The first 

 modification is termed " dendroid " (" baumformig "), and is characterised as follows : — 

 " The dendroid type is the most primitive and simple, but nevertheless the rarest 

 modification. It is to be fouud in Leucetta primigenia, Leucyssa cretacea, Leucandra 



1 Vosmaer, Report on the Sponges dredged up in the Arctic Sea by the "Willem Barents," in the years 1 S 7S and 

 1379, NiederldnJ. Archivf. Zool, Supplement-Bd. i. 1882. 



