FOURTH REPORT OF THE DIRECTOR KJO/ 155 



growing obliquely upward from the very beginning of the coral 

 (Monticulipora) growth. This soecimen is from the Onondaga 

 limestone. 



A very similar combination is sho\^n in figure 3, plate i, which 

 represents a colony of Favosites sphericus (Helder- 

 bergian) with worms of like character. Figures i, 2 are of a 

 Stromatopora from the Cobleskill (Uppermost Siluric) limestone, 

 one showing the worm apertures on the weathered surface, the 

 other being a polished face of the same specimen with many 

 cross-sections of oblique tubes. 



The tabulate coral Pleurodictyum ; the worm Hicetes innexus; 

 a sponge, and the gastropod Loxonema (sometimes Pleurotcmaria) 

 or the brachiopod Chonetes [see plates 3, 4]. This is a very remark- 

 able and most instructive combination and we have illustrated it 

 quite fully on the accompanying plates. The combination of the 

 coral and the worm has long been known and the sandstone casts 

 of the base of Pleurodictyum with the "coiled central body" or 

 "wormlike object" are common in the Low^er Devonic (Coblentzian) 

 of Germany and have frequently been illustrated. 



Pleurodictyum is a compound coral growing in smiall lens shaped 

 colonies with large cells and the genus is widely distributed in 

 faunas of Lower and Middle Devonic time. We may mention P. 

 lenticulare Hall of the Helderbergian of New^ York and its 

 variety' laurentinum of the Grande Greve limestone of 

 Gaspe; P. c o n v e x u m Hall, Onondaga limestone ; P. p r o b 1 e - 

 m a t i c u m Goldfuss of the Coblentzian; P. constantino- 

 p o 1 i t a n u m Archiac and Verneuil, from the lowest Devonic of 

 the Bosphorus ;P. amazonicum Katzer of a similar age in the 

 Amazonas and P. s t y 1 o p o r u m Eaton from the Middle Devonic 

 Hamilton shales of New York. The concurrence of the coral and 

 its convoluted worm has been noted in several of the species here 

 mentioned but the varying degree of its frequency is instructive. 

 Thus in the earliest species, P. lenticulare, I have seen the 

 worm tube very rarely, after the examination of a considerable 

 number of examples ; in the var. laurentinum not at all ; 

 never in the large species P. convexum Hall of the Onondaga 

 limestone. The single illustrations of P. amazonicum and 

 P. constantinopolitanum show its presence but enable 

 one to form no conception of its prevalence. The combination is 

 frequent enough in P. p r o b 1 e m a t i c u m to have given rise to 

 the specific name of the coral. The Middle Devonic P. stylo- 



