THE THALIACEA. 91 



1). P horozooiils . 

 DoLiOLUM Tmtonis, Herdman. 



This was taken in 13 hauls, all between 100 fathoms and the snvface. Of the 119 

 specimens which I have assigned to it, a few may have been young gonozooids ; but the 

 greater number (31) of minute specimens, which did not clearly show either generative 

 organs or dorsal otitgrowth, have not been reckoned as either gonozooid or phorozooid. 

 No specimen exceeded 4 mm. in length. As we do not know at what length the phoro- 

 zooids become freed, and as so many minute bat recognizable gonozooids were captured, 

 it must be left uocertain whether the larger phorozooids had been kaocked off the dorsal 

 outgrowtli of a hlastozooid, or were leading an independent existence ; the former Avas 

 probably the case. Blastozooids which I refer to Tritonis were present ia all the hauls 

 in wliich these phorozooids were taken. 



DoLiOLUM sp., Borgert. 



To this may be referred two specimens (35 o, 250-150 fathoms ; 35 k, 130-300 fathoms) ; 

 and, with less certainty, on account of imperfect preservation, eleven farther specimens 

 (21 w, 500-400 fm., 4 specimens; 21c, 300-200 fm., 1 specimen; Zl d, 1000-750 fm., 

 1 specimen ; 27 «, 1250-0 f rn., 5 specimens). No generative organs were seen, and the 

 specimens were therefore probably phorozooids. 



c. Blastozooids. 



Very little is known of the specific characters of blastozooids. From the text and 

 figures of the more recent authorities I have compiled the following table, omitting, 

 however, two characters which are found in some definitions — the thickness of the 

 muscle-bands, because this seems to depend upon age and size ; and the shape of the 

 true stolon, which appears (from my specimens, at any rate) to alter in successive phases 

 of maturation and germination. 



In the tabic, to save space, the muscle-bands are represented by i, ii, iii, &c., the intermuscular spaces 

 by i-ii, ii-iii, &c. Tiie authorities, indicated by square brackets iu the table, arc : — 



A. Borgert: 'Plankton-Expedition. Thaliacea. — C. Vertheilung dcr Dolioleu ' [Krohni, pi. vi. 

 fig. 13). 



C. Grobben: Arb. Zool. Instit. Wien, iv. 201 [Miilleri, pi. iii. figs. lG-18; denticulatum, pi. i. 

 figs. 3-5, pi. ii. fig. 7). 



13. Uljauiii : Fauna u. Flora d. Golfes v. Neapel, Monographic Z)o/«o/«»e {Miilleri, pi. vii. fi''. 1] 

 pi. ix. fig. G ; Ehrmbergi, pi. xii. fig. 8). On p. 128 the anus of Miilkri is described as opeuiu" 

 in v-vi, but is drawn as lying in vii-viii on pi. vii. fig. 11 : this figure seems to be wrong in some 

 other respects — for example, the eighth muscle-band curves into the dorsal stolou and not the 

 seventh. 



15" 



