ZOOLOGICAL AND BOTANICAL ASSOCIATION. 213 



Montacuta bidentata (Montagu). 

 I have met a few of this species in the light-house deposits. Only 

 dead specimens have been taken in the bay. 



Turtonia minuta ( Otho Fabricius). 

 A few specimens of this minute shell (the well-known Montacuta 

 purpurea) were met with, having their purple hue in perfect preserva- 

 tion. It is sometimes found living in abundance in the harbour. 



Mytilas edulia (Linneus). 



Several varieties of this variable shell occurred in vast numbers in 

 the bluish clay. The size was generally above the average of recent 

 specimens, one individual measuring three and a half inches in length, 

 and two and three-quarter inches in breadth. There was often a great 

 accumulation of nacreous matter inside the valves, in consequence of 

 Buccinum undatum piercing the outer coat of the shell. It is an inhabi- 

 tant of the bay to such an extent that it was put forward as a promi- 

 nent item of likely traffic when the Belfast and Holywood Railway was 

 in contemplation. 



Modiola modiolus (Ltnneus). 

 A fragment of this species occurred in the former beach of Jordans- 

 town, four feet above present high- water mark, along with twenty-two 

 other species regularly deposited in a thin bed ; common as a living 

 form in the bay. 



Modiola tulipa (Lamarck). 

 "Was found pretty frequently in single valves, of a size rivalling 

 those of its congener Edulis. The coloured rays were almost obsolete. 

 The species still inhabits the harbour. 



Nucula nucleus (Linneus). 

 This species, so well known by the Lamarckian designation, Marga- 

 ritacea, appeared somewhat frequently in the sandy mud, of large dimen- 

 sions. Most of the individuals exceeded half an inch in length, and 

 were nearly as much in breadth. It still belongs to the Fauna of the 

 neighbourhood. 



