3. (Arthropoda: Crustacea) The median pointed process at the end of the cephalothorax. a. In thoracic barnacles, a valve between the lateral and opposite carina at the basiscutal end of the capitulum; simple and bearing alae in many balanomorphs, but compound and overlapping the laterals in higher balanomorphs. See also compound rostrum.
See also: beak. b. The spine anchored on the posterior end of a cuttle bone and some pens. 7. (NEMATA: Secernentea) In Aphelenchida males, the beak-like projection ventrad near the proximal end of the spicule, joining the dorsal and ventral spicular shafts.