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226 FAMILY GLOBIGERINIDA. 



mode of communication between their cavities, we find that their liorizontal partitions or 



floors are perforated by numerous large pores (Plate XV, figs. 2, 3, 4) which closely resemble 



those of the shell of a Botalia or a Planorhulwa in their size and arrangement ; and these 



will allow of free communication, by pseudopodial threads of sarcode, between the segments 



that are lodged in the chambers piled vertically one over the other. The vertical partitions are 



V VV1-T much thicker, and are not thus minutely and regularly perforated ; but 



r IG. AAAvi. 



they exhibit a small and variable number of large apertures (fig. 4, a, a), 



that lead into the adjacent cells which lie in or near the same horizontal 



_5s «2 plane. I say in of near, because it is seldom if ever the case that the 



-^p horizontal partitions or floors of two adjacent vertical piles of cells are 



~^___2* on the same level ; and, in fact, the typical arrangement (though fre- 



quently departed from) seems to be, that there is an alternation in the 

 levels of the floors of adjacent piles (as shown in the accompanying 

 diagram, based on some parts of fig. 3), and that every chamber in any pile b normally com- 

 municates with two chambers in each of its adjacent piles a and c, by one passage above 

 and the other below the floor that divides them. Neither the horizontal floors nor the 

 vertical partitions consist of more than a single lamella. 



395. TiNOPOBUS BACULATUS. — The original t3'pe of the genus, namely, the T. haculatus 

 of De jNIontfort, agrees closely with T. vesicularis in the fundamental characters of its organiza- 

 tion, but differs in being furnished with a variable number of radiating appendages that give 

 it a strong external resemblance to Calcarina. Of the specimens in my possession, the 

 greater part present the aspect represented in Plate XV, figs. 6, 7, and on a larger scale in 

 fig. 5 ; and these were collected from coral reefs in various parts of the Polynesian Archi- 

 pelago, — my earliest acquisition of them, however, having been from the contents of the 

 stomach of an Eehinus taken on the coast of Borneo, which were kindly put into my hands by 

 Dr. J. E. Gray. I am informed by Mr. Denis Macdonald that on certain coral islands which 

 he has particularly examined, these organisms are so extraordinarily abundant, that they 

 accumulate in the lagoons in regular strata, commonly alternating with strata of OrbitoUtes. 

 The more massive and ruder forms represented in Plate XV, figs. 8, 9, occur in Mr. Cuming's 

 Philippine collection. 



396. External Characters. — The typical form of the central portion of Tinoporns baculatus 

 may be considered as an oblate spheroid; sometimes, however, the organism is nearly 

 spherical, and sometimes it is much flattened out, especially when the body extends itself 

 into the radial prolongations. Its surface is divided into areolos (fig. 5) very much as in T. 

 vesicularis ; but the angles of junction of the partitions between the areolae ai-e very commonly 

 occupied by rounded projecting tubercles, strongly resembling those of Calcarina. The 

 number and size of these tubercles vary greatly among different individuals, as will be seen 

 on comparing figs. 6 and 7. They seem to be altogether wanting in the Philippine specimens, 

 being apparently replaced by a multitude of small spines, which give to the surface a hispid 

 aspect. From the marginal portion of the central disk there spring a variable number of 

 conical prolongations having the furrowed surface of those of CV//fw;'»«; and these appear 

 seated (so to speak) upon extensions of the central disk itself, which is sometimes so deeply 



