66 PEOCEEDINGS OP THE NATIONAL MUSEUM vol.72 



Biology. — According to Osburn, the zoarium encrusts shells, coral, 

 and sponges. All our specimens were unilamellar and free; they 

 creep over fragile, destructible, or easily detached organisms. 



The ectocyst is, according to the rule, light colored; it is of the 

 same color as the nullipores on which the zoarium is often attached; 

 we have thus the beautiful rose-tinted specimens attached to nulli- 

 pores of the same color. Moreover, "the color varies from pink to 

 reddish brown" (Osburn). 



The ovisac containing the eggs and embryos is placed in the distal 

 portion of the ordinary (not mandibular) zooecia in the vicinity of 

 the vestibule. The spermatic cells are dispersed in the general cav- 

 ity of the two kinds of zooecia. 



Because of its large dimensions, this species even when living is 

 easily encrusted by the small species of bryozoa. The latter develop 

 very rapidly on the ectocyst; they are not in the least disturbed by 

 the movement of the mandibular operculum which they impede 

 when the latter remained closed for a long time. We have several 

 colonies dredged alive on which three or four cellules are entirely 

 covered and rendered immobile by the small Membranipores or Crib- 

 rimorphs. The instinct of the larvae of these parasites is quite re- 

 markable, for they appear to understand that the large animals can 

 subsist only when in the midst of great planctonic richness. 



This is a species of shallow water from 15 to 50 meters. It can 

 live at greater depths; Ortman noted it from Japan to 320 meters 

 and we ourselves have observed it from the Philippines at 283 and 

 372 meters, but these are the exceptional cases in which the specimens 

 are rare or dead. It is very vigorous and almost universal, for it has 

 been observed in all the oceans. It is especially equatorial, but it 

 passes beyond the Tropics, for it is found in the Pacific as far as 

 Japan and the Sandwich Islands. As it does not encircle a single 

 continent, it must have found a passage of dissemination in the 

 ancient seas. In fact, it is already known in the fossil state in the 

 American and Australian Miocene, Perhaps our Steganoporella 

 parvula from the lower Miocene of Bowden, Jamaica, is the primitive 

 and ancestral variety. In Europe it is replaced by the superb Steg- 

 anoporella elegans Milne Edwards, 1838, very common in all the 

 Miocene formations. 



Occurrence.— Albatross Station D. 2324 north of Cuba; 23° 10' 25" 

 N.; 82° 20' 24" W.; 33 fms.; coral. 

 Albatross Station 2327, north of Cuba; 23° 11' 45" N.; 



82° 17' 54" W.; 182 fms.; fine brown sand. 

 Albatross Station D. 2365, east of Yucatan; 22° 18' 

 00" N.; 87° 04' 00" W.; 24 fms.; white rock coral. 

 Albatross St&tion D. 2405, Gulf of Mexico, 28° 44' 

 00" N.; 85° 16' 00" W.; gray sand. 



