90 Prof. M'Intosli's Notes from the 



with the neck, and two teeth and traces of a third occur on 

 the crown, those in the front of the body being considerably 

 altered, and there are no gular bristles. 



The variety of Nicomache maculata with four spine- 

 bearing segments and the pigment on the head simulating 

 eyes approaches Arwidsson's Nicomache quadrispinata. Few 

 examples are collected in a perfect condition, and regene- 

 rated anterior and posterior ends are common. The intestine 

 is filled with the greyish mud of its habitat, containing sand- 

 grains, sponge- spicules, diatoms, radiolarians, and other 

 debris. 



The third British form is Prodymene mulleri, which was 

 dredged in 78 fathoms off the Outer Skerries in 1868 by 

 Dr. Gwyn Jeffreys, and which also was found by Prof. G. S. 

 Brady off the coast of Northumberland. In this the head is 

 distinguished from that of Praxillura by the narrow rim of 

 the cephalic plate, a condition which renders the anterior 

 process of the keel prominent. The plate slopes from 

 behind forward and downward, and terminates anteriorly in 

 the median process, which is as well developed as in Praxil- 

 lura prcetermissa, but, instead of being bounded by the fissure 

 between it and the cephalic rim, it is continuous at its base 

 with an accessory fold on each side wiihin which the anterior 

 curve of the nuchal organ is situated. Arwidsson * makes 

 no differentiation of the base of the anterior process, so that 

 something depends on the preparation if variation does not 

 occur. From the median process a short and narrow keel 

 passes backward, but it does not reach the middle of the 

 cephalic plate. On each side of the keel is the short though 

 deep nuchal groove, which terminates anteriorly by curving 

 outward and being lost behind the accessory fold on each 

 side of the central process. The rest of the surface of the 

 cephalic plate is smooth. The margin of the slightly 

 hollowed cephalic plate is comparatively thick, but is little 

 elevated, and, though slightly crenate, it has no distinct 

 notch ; yet in the preparation a shallow groove runs from 

 one of the crenations in the mid -lateral I'egion, and also 

 extends to the first bristled segment. The fused prostomial 

 and peristomial region is narrow dorsally but wide ventrally, 

 and has the mouth as a somewhat triangular opening beneath 

 the median process, which is grooved by the anterior depres- 

 sion from the mouth. The posterior lip is transverse and 

 prominent. 



* Skandinav. u. arktische Maldau. Taf. iii. fig. 93. 



