328 Trmisactions. — Zoology. 



striction. I believe I am right in considering my species quite 

 distinct from his, whatever may be their fate with regard to 

 those of other observers. 



With regard to Cystodytes, I have ah'eady expressed a doubt 

 as to the specific importance of C. 2]crs2)icuus, and tolerate it 

 only because I feel that 1 do not know it well enough to reject 

 it. But G. auchlandicus is so well marked by its test-structure 

 that there is no doubt of its complete separation from both 

 C. draschii and C . i^hilippinensls, Herdmau. The distribution 

 of the genus (Mediterranean, Brazil, Philippines, New Zealand) 

 probably indicates the existence of numerous species yet un- 

 discovered, or the previous existence in geological time of con- 

 necting links now lost. Our species approximates more closely 

 to the Brazilian form, however ; though in the vacuolated 

 character of the upper test-layer it suggests C. philvpinnensis. 



Lastly, we have to deal with the anomalous genus which I 

 have ventured to name Polysyncraton. Here we scarcely 

 know which way to turn. The thin colony, the four rows of 

 branchial stigmata, the large atrial languets, are all features 

 which suggest the genus Lcptoclinum as the natural home of 

 the two species. To this also the spirally-coiling vas deferens 

 lends strength, as does the presence of stellate spicules in the 

 test, and the six-lobed branchial siphon. But the structure of 

 the male reproductive bodies is exactly that discovered by 

 Herdinan in his Ccelocormus Imxleyi, for which he founds the 

 family Coelocormid^. (See "Challenger" Eep., pt. xxxviii., 

 p. 317.) The single species composing this family also possesses 

 stellate spicules, but the siphon is five-lobed, there are no 

 bladder-cells in the test, and only one common cloacal aper- 

 ture placed in the bottom of the cujplike colony. The curious 

 ovary is, as far as I am aware, quite unique in Polysyncraton. 



But in L. densnm I have noted a tendency to division in 

 the single spermatic mass, characteristic of the Didemnidse. 

 May not this be suggestive of the state of things met with in 

 Polysyncraton and Coelocornms ? And, if so, a still stronger 

 link between the Coelocormidae and Didemnidge would be 

 afforded by the new species, possessing as they do the corm 

 characteristic of the latter with the form of reproductive bodies 

 met with in the former, but also faintly foreshadowed in the 

 latter group. 



Where then must Polysyncraton be placed? The most 

 obvious method of avoiding all trouble is to at once found a 

 new family for its reception, midway between the two groups 

 to which it is allied. But this, though easy, is open to objec- 

 tion, for systematic classification, at present cumbersome 

 enough, would speedily become a scientific nuisance were 

 every strongly-marked genus at once constituted a family. 



A second course is to unite the connected families on the 



