MAXX DIATOMS OF THE ALBATROSS VOYAGES. 31 



arc synonymous AviLli //. tnrffelra: II. coniprcssa "Wall. /if //. fnauriliaria BcTgor,^ II. hor- 

 yana Pant, f- Triccmtiam javanicuni Clevi}. ^ Bui there is doubt whether these belong 

 here. Tliey would be wvy widely divergent varieties, and it seems best to h\ive them 

 in a combination by ihemselves under the sp<x'ific nam(^ triqueira. T, [Phurodcsmium) 

 hrehusonii Kiitz., though an evident Terpsinoe, is also in strong enough contrast to 

 stand specifically. I liave based this conclusion on a careful comparison of the two 

 species in H. L. Snaith's type no. 388 {P. brcbissonii) and no. 590 (T. musica) and on 

 the agreement of these willi (he figures of Kalfs in Pritchard's History of Infusoria.^ 

 Found at station 2807, Galapagos Islands. 



PORPEIA Bail. 



Porpeia Bail. ; Pritdi. Hist. Infus. ed. \. 850. pL G.f. G. ISGl . Rabh. Fl. Eur. Alg. 1: 

 315. 1804. Grev. Trans. Micr. Soc. Loud. n. s. 13: 52. jyJ. G, /. 18-21. 1805. De 

 Toni, Syll. Alg. 2: 893. 1892. Van Ileur. Treat. Dial. 477./ 208, 1890. Boyer, 

 Proc. Acad. Phila. 1900: 781. 1901. 



This genus is a connecting link Ijetween Bid(hilphia Gray and Ilemiaulus Ehrenb. 

 Its di fference from the former is largely a nuitter of greater ma^ssiveness of frustuh^ and 

 the internal septa; its difference from the latter is in the absence of straight or curved 

 spines at the ends of its [)rocesses an<l in its septa. In fact, a study of the zonal Aiew 

 of t hese genera will show how little is needed to turn (me into the other. Schmidt in his 

 Alias / has figured a species which, as he says, is highly interesting, aHemiaidus-Porpeia 

 with a rudimentary curved spine at the end of each process. Or, if w^<^ take figure 42 

 of the same plate and broaden laterally its central (4evatioii till it ])resses on tlie two 

 processes, we have a Porpeia, and the two sutur(^s between the central area and the 

 processes reproduce (exactly the septa of Porpeia. But tliough this genus could in a 

 broad sense be united with either of the otlier two, Ilemiaulus could nt^t be included 

 in Biddulphia without abandoning entirely our present concepti<m of it. For classi- 

 fication it is, therefore, certainly best to retain this genus, as is universally done, 



Porpeia quadriceps Bail.; Pritch. Hist. Infus. ed. 4. 850. pi. G. f. G. 18fil. Van Ileur. 



Synop. pi. 95bis. /. 12-14- 1881, Grev. Trans, Micr. Roc. Lond. n. s. 13: 52. pL 



6./ 18-19 (pi 8, f, 13 doubtful). ISOo. Schmidt, Atlas pi. 142. J. 38, 4r>-5G. 1889. 



Van TTeur. Treat. Diat. 477. 1890. l)(^Toni, SvU. Alg. 2: 893. ]894. Moeb. Diat.- 



taf. pi 67. f. 18-19, (pi. 68. /. 13 doubtful). 188h Wolle, Diat. N. A. pi. 66. f. 



25 (/. 30 doubtful). 1890. Boyer, Proc. Acad. Phila. 1900: 731. 1901. 

 Porpeia quadrala Grc^v. Trans. Micr. Soc. Lond, n. s. 13: 53. pL G. f. 20. 1865. 



Moeb. Diat.-laf. pi. 61. f. 20. 1890. De T(mi, Syll. Alg. 2: 893. 1894. Van Ileur. 



Synop. pi. 95bis.f. 15. 1881; Treat. Diat. 477./. JOS. 1S9(>. Wolle, Diat. N. A. pL 



66. f. S3, 1890. Boyer, Proc. Acad. Phila. 1900: 732. 1901. 

 Porpeia orna/a Grev. Trans. Micr. Soc. Lond. n. s. 13: 53. pi. G.f. 21. 18()5. Moelx 



Diat.-laf. pi 67, f. 2U 1890. Di; Toni, Syll. Alg. 2: 894. 1894. 

 Porpeia robusta Truan & Witt, Diat. Hayti 18. pi 5. /. 23, 1880? De Toni, 



Syll. Alg. 2: 894. 1894. 

 Porpeia injlexa Sclunidt. Atlas pi 142. J. 58. 1889. 



I think Schmidt does rightly in cojnl)ining liis fourteen figures above cittnl under 

 this single species. They practically are identical; figure 47 is what (freville calls P, 

 quadrala^ and his figures 54 and 5Gar<' (in^ville's P. ornata. But I can see no reason 



a Op. cil. 252. pi 13. f. 7-12. 



h Le Diatomiste 1: 31. ]>l 51. pi, 5. J. 8. 1890. 



cPanl. Beitr. BacilL Ung, 2: 82. pi 30. f. 420, 423, 1SS9. 



^Bih. Sv, Vet. Akad, IlandL 18-^: 24. pi G.f. 15. 1881. 



fiEd. 4. 859, pi 11, J. 41. 18G1. 



f PI 142 J. 57. 



