500 R. ETHERIDGE ON ADHERENT CARBONIFEROUS PRODTJCTIDJE. 



both collected by Mr. James Bennie — one during a visit to Scremer- 

 ston quarry ; the other whilst examining a section of the Fifeshire 

 coast near Kinghorn. We have in Figs. 2 and 3 a small Brachiopod, 

 differing in many respects from the adherent Producti, but clinging 

 to a Productus-sipme by its own hinge-spines in such a manner that 

 the interior of the ventral valve is exposed to view. The hinge - 

 line, was, when perfect, in all probability equal to the width of the 

 shell ; but in its present state the auricular expansions are to a great 

 extent broken away. The shell is in form roundly oblong and has 

 become attached to the Productus-spine not only by its own hinge-spines 

 but also by the umbonal and visceral region, in a similar manner to 

 the mode adopted by Productus complectens, mihi. The muscular 

 scars or other internal characters of the specimen are not discernible ; 

 but although viewed from the interior, the longitudinal ribs covering the 

 shell are quite visible. Of the latter, there are, I think, about sixteen, 

 large and well-marked for the size of the shell, and one or two 

 perhaps exhibiting traces of bifurcation. In addition to the fixation 

 derived from the union of the visceral portion of the shell with the 

 object of attachment, adherence is effected with the assistance of 

 three spines, differing in size. The largest of these arises imme- 

 diately from one end of the hinge-line, as far as preserved, and 

 passes directly over and round the Productus-s-pme. The two other 

 spines which assist in the anchoring of the shell, but which are 

 much smaller than the first one named, span the Productus-spme in a 

 contrary direction, and are only partially visible. 



Unfortunately for the purposes of identification the hinge-line of 

 this little shell is imperfect ; but when compared with the adherent 

 Productus we see that the mode of attachment is essentially the 

 same, although the longitudinal and radiating ribs give it a character 

 essentially its own, and one not seen in Productus complectens. 

 However, before going further with this branch of the subject, it 

 will perhaps be better to first examine the second specimen 

 (Fig. 4). 



In this case we have before us also a ventral valve, adhering by 

 the whole of its surface to an Encrinite stem, with a series of 

 spines radiating from it (c, c), some of the latter, as in the case of 

 those of Productus complectens, leaving grooves in the substance of the 

 stem when removed, and showing that in a similar manner a certain 

 amount of increase took place in the Crinoid stem after the shell 

 had attached itself. There may be seen a well-marked hinge-line 

 possessing what seems to be a distinct area and median fissure (a), 

 although the latter appears larger than it should do from the ac- 

 cidental fracture of some of the neighbouring shelly matter of the area, 

 but still not sufficiently so to alter its general character. The largest 

 spines (b) proceed from each extremity of the hinge-line or area(?), 

 whilst from one side of the shell several others radiate out over the 

 surface of the Crinoid stem, and one or two from the opposite side 

 (c, c). The state of preservation of this specimen is such that very 

 little more can be said about its general characters, except that along 

 the front there are a few indistinct crenulations (d) which may 



