A GROUP OF PECULIAR MOLLUSKS 95 



Verv little is known, even to scientific men, about Permian vertebrates. 

 There are not half a dozen scientific men in this country who have any 

 considerable first-hand knowledge of them, or half a dozen museums in 

 the w^orld that possess any considerable collections, and nowhere else 

 have the specimens been so carefully prepared for study and exhibition 

 as in the American Museum. The skulls and skeletons recently pre- 

 pared here have not yet been thoroughly studied, but they will supply 

 most important evidence regarding the early history of the land verte- 

 brates, the manner, the conditions, and the causes of their development, 

 their relations to the modern reptiles, amphibians and mammals. Upon 

 the imperfect evidence hitherto available have been built various theories 

 and hypotheses of relationship and development, which will have to be 

 revised and modified in many cases, in view^ of the new evidence already 

 at hand. 



W. D. Matthew. 



A GROUP OF PECULIAR MOLLUSKS. 



MR. A. DE Costa Gomez has presented to the Department of 

 Conchology an interesting group of shells of the mollusk Ver- 

 micular i a':! nigricans Dall (old nomenclature Vermetus varians 

 D'Orb., var. irregularis D'Orb.). The specimen is a tightly coiled 

 mass of tubes, a gorgon-like maze of tortuous pipes which look so much 

 like the cases of the annelid genus Scrpula that they appear rather 

 incongruously referred to mollusks. 



These anomalous mollusks were separated by Cuvier in 1830, and 

 by him erected into an order. They are true prosobranchs, though in 

 their shelly covering they have widely departed from any conventional 

 shell design. The shells are usually attached to other shells or to corals, 

 or they live in sponges, or again, as in this example, they unite to form 

 large colonies. They are unisexual, oviparous, or viviparous, antl the 

 eggs are often found in the tubes. The animals are dark purple-brown 

 in color with reddish dots. This species makes the so-called "worm 

 rock" of West Florida. The masses of tubes are sometimes dangerous, 

 like coral reefs, to boats in shallow water. Dall has observed patches 20 

 or 30 feet in diameter with the top nearly level and barely dry at ordi- 

 narv low water. 



