14 University Geological Survey of Kansas. 



AMBLYSIPHONELLA. 



Amblysiphonella prosseri. Plate I, figs. 2-2f ; plate II, fig. 6. 



Ambly siphonella prosseri Clarke, Amer. Geol., xx, p. 387, pi. xxiii, ff. 

 1-9, (1897). 



Clarke's description : " The bodies from Netawaka and Weep- 

 ing Water are simple subcylindrical individuals, straight or 

 gently curved, the largest fragment measuring 70 mm., and in- 

 dicating an entire length of not exceeding 100 mm. The fossils 

 are from a calcareous shale and have, for the most part, been 

 somewhat compressed. Their interior cavities, the cloaca and 

 interseptal chambers, are filled with compact gray limestone, 

 distinctly and fine oolitic, and their exteriors are frequently 

 entangled with encrusting Bryozoa and the remains of other 

 fossils. The septate or annulate aspect of the exterior is always 

 shown, and when this external surface is free from other or- 

 ganic remains and cleansed from the attached matrix, it presents 

 the aspect of a Fistidipora or of a small-celled Alveolites; that 

 is, the meshwork of the skeleton is made up of polygonal cells, 

 all of a small size, not always opening directly outward, but in 

 places frequently presenting oblique apertures. So fine is this 

 superficial network, and so uniform the size of the cells, that 

 one might casually interpret the entire fossil as a macerated 

 Orthoceras, overgrown with an encrusting bryozoan. 



" One of the specimens is preserved with its aperture entire, 

 which shows it to have been a simple, narrow, circular cavity. 

 On cutting these bodies along their longer axis, we observe, first, 

 a continuous central cloaca, relatively much wider than would 

 be the siphon of an orthoceran of the same size, but slightly 

 constricted at intervals, where its walls meet the septa. This 

 cloaca is delimited by a well-defined circular wall, and thus has 

 no communication with the septal chambers or the cavities of 

 the annuli, except through the perforations in this wall. The 

 septa are at quite regular intervals and are convex upward. On 

 the gastral surface they project slightly inward, as observed, 

 into the cloaca. Each of these septa presents a former apertural 

 surface, and the sponge affords, thus, an interesting instance of 

 periodical intensity of growth force. The walls of the sponge 



